Image processing system and method for providing image quality stabilization processing in devices on a network

ABSTRACT

In an image processing system in which a plurality of image processing apparatuses and a management apparatus are connected to each other via a network, the management apparatus forms the image processing apparatuses into one or more groups based on apparatus attribute information, acquires control variable value information from an image processing apparatus in a group, and sends the acquired information to the other image processing apparatuses in the group. The other image processing apparatuses receive the control variable value information sent from the management apparatus, and execute image processing based on the received information.

This application is based on application no. 2001-102624 filed in Japan,the content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image processing system, amanagement apparatus, an image processing apparatus, a managementmethod, a computer program, and a storage medium, the system includingthe management apparatus and a plurality of image processingapparatuses, which are connected to each other via a network.

2. Related Art

In printers and other known image processing apparatuses a reduction inimage quality levels occurs when jobs are executed continuously underfixed control conditions. Variations in internal temperature and wearand tear on the photosensitive drum and other structural elements, forexample, result in the image density and image positioning relating toexecuted jobs failing to meet target control values, and the qualitylevel of processed images (hereafter “image quality level”) suffers as aresult. In order to counter this deterioration in the image qualitylevel, image quality stabilization processing is conducted in knownimage processing apparatuses to fine tune the control conditions inaccordance with the existing environment of the apparatus.

In the image quality stabilization processing, control variables thataffect image quality in the image processing apparatus are determined.If the image processing apparatus is a printer or similar image formingapparatus, tests are conducted to detect the density of a plurality oftoner patterns of differing densities formed on the surface of thephotosensitive drum as part of the test process, and the optimaladjustment values for control variables such as the developing biasvoltage of the developing unit and the grid voltage of the charging unitare determined based on the test results. Other control variablesaffecting image quality include heater output and the oil supply levelsof the heat fixing unit.

If the image processing apparatus is a scanner or similar image readingapparatus, on the other hand, control variables include the exposurevoltage applied to the exposure lamp.

Execution of the image quality stabilization processing in an imageprocessing apparatus naturally requires a certain amount of power usage.In the case of a printer, for instance, a surprisingly high amount ofpower is needed to rotate the photosensitive drum and to drive thecharging unit in order to form the toner pattern on the surface of thephotosensitive drum.

Moreover, the recent increase in the number of business officesoperating a plurality of image forming apparatuses connected via a localarea network (LAN), means that major power consumption is required toexecute the image quality stabilization processing in all of theseapparatuses.

A result of the enhanced focus in recent years on the depletion ofenergy resources has been a comprehensive move across a broad spectrumof fields to achieve reductions in power consumption. Thus the increasedpower usage of businesses operating a large number of image formingapparatuses is of major concern.

Of course, this problem relates not only printers and other imageforming apparatuses as but also to image reading apparatuses such asscanners or any other image processing apparatus that executes imagequality stabilization processing.

SUMMARY OF THE INVENTION

In view of the issues discussed above, a first objective of the presentinvention is to provide an image processing system that reduces thepower requirements of executing image quality stabilization processingin a plurality of image processing apparatuses connected via a network.

A second objective is to provide a management apparatus included in theimage processing system.

A third objective is to provide an image processing apparatus includedin the image processing system.

A fourth objective is to provide a management method used by themanagement apparatus.

A fifth objective is to provide a computer program for having amanagement apparatus execute the management method.

A sixth objective is to provide a computer-readable storage medium forstoring the computer program.

The first objective can be achieved by an image processing system havinga management apparatus and a plurality of image processing apparatuses,in which the management apparatus is connected via a network to eachimage processing apparatus and includes (a) a first acquisition unit foracquiring apparatus attribute information showing an attribute of eachimage processing apparatus, (b) a group formation unit for forming theimage processing apparatuses into one or more groups based on theacquired apparatus attribute information, (c) a second acquisition unitfor acquiring value information from a target image processingapparatus, the target image processing apparatus being an imageprocessing apparatus in a group, and the value information showing acontrol variable value required by the target image processing apparatusin order to execute image processing, and (d) a transmission unit fortransmitting the acquired value information to another image processingapparatus in the group; and each image processing apparatus includes (a)a reception unit for receiving the value information transmitted fromthe management apparatus, and (b) an image processing unit for executingthe image processing based on the received value information.

This structure of the invention allows for image processing to beexecuted for a plurality of image processing apparatuses in a groupbased on control variable values determined as a result of the imagequality stabilization processing executed in one of the image processingapparatuses, without it being necessary for the other image processingapparatuses to conduct the stabilization processing. The invention thusallows for an overall reduction in the power usage required to executeof the image quality stabilization processing.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects, advantages and features of the invention willbecome apparent from the following description thereof taken inconjunction with the accompanying drawings that illustrate specificembodiments of the present invention.

In the drawings:

FIG. 1 shows an exemplary structure of an image processing system 1according to a first embodiment;

FIG. 2 is a block diagram showing a structure of a server 100 includedin image processing system 1;

FIG. 3 shows the content of a machine information table 121 in server100;

FIG. 4 is a graph showing an exemplary environment volatility of anarbitrary printer included in a printer group 500;

FIG. 5 is a graph of exemplary image quality attribute informationrelating to printers 501 to 503;

FIG. 6 shows the content of a management information table 122 in server100;

FIG. 7 shows the content of a job management table 123 in server 100;

FIG. 8 is a flowchart showing the processing executed in server 100;

FIG. 9 is a flowchart showing a machine information reception processingsubroutine;

FIG. 10 is a flowchart showing a group formation processing subroutine;

FIG. 11A shows an exemplary group formation conducted by server 100 on aplurality of external apparatuses;

FIG. 11B shows an example of the group formation processing beingexecuted on the group formation in FIG. 11A;

FIG. 12 shows an exemplary structure of a group allotment tablecontaining information relating to a group allotment range;

FIG. 13 is a flowchart showing a time-based stabilization scheduleprocessing subroutine;

FIG. 14 is a flowchart showing a scheduled stabilization time adjustmentprocessing subroutine;

FIG. 15 is a schematic diagram showing scheduled stabilization timeadjustment processing and image quality stabilization processing beingexecuted with respect to six external apparatus A to F, that have beenformed into two groups E1 and E3 in the group formation processing, thestabilization processing being executed in the order A, B, C withrespect to group E1, and D, E, F with respect to group E3;

FIG. 16 is a flowchart showing a job allotment processing subroutine;

FIG. 17 is a schematic diagram showing the relationship betweenoperation time and image quality in three arbitrary externalapparatuses;

FIG. 18 is a flowchart showing an execution sequence processingsubroutine;

FIG. 19A shows an example of the image quality stabilization processingbeing conducted after executing a job;

FIG. 19B shows an example of the image quality stabilization processingbeing conducted prior to he job being executed;

FIG. 20A shows an example of the image quality stabilization processingbeing conducted after executing a print job;

FIG. 20B shows an example of the image quality stabilization processingbeing conducted prior to the print job being executed;

FIG. 21 is a flowchart of the processing conducted in each externalapparatus after power has been supplied;

FIG. 22 is a flowchart showing a quantity-based stabilization processingsubroutine according to a second embodiment;

FIG. 23 is a flowchart showing an image processing operation numberadjustment processing subroutine according to the second embodiment;

FIG. 24 is a flowchart showing a job allotment processing subroutineaccording to a second embodiment;

FIG. 25 is a schematic diagram showing the relationship between imagequality and the number of image processing operations in three arbitraryexternal apparatuses;

FIG. 26 shows an example of requested jobs being allotted to one ofexternal apparatuses A, B, and C, in the job allotment processing;

FIG. 27 is a flowchart showing an execution sequence processingsubroutine according to the second embodiment;

FIG. 28 shows an exemplary structure of an operation panel 520 in anarbitrary external apparatus;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An image processing system 1 of the present invention is described belowwith reference to the diagrams.

First Embodiment

FIG. 1 shows an exemplary structure of image processing system 1(hereafter “system 1”) according to a first embodiment of the presentinvention.

System 1 includes a server 100, personal computers 301, 302, 303, . . .(PC group 300), scanners 401, 402, 403, . . . (scanner group 400),printers 501, 502, 503, . . . (printer group 500), and a personalcomputer 200 (hereafter “manager PC 200”) operated by a manager in orderto manage system 1. The elements of system 1 are connected to each othervia a LAN or similar network.

Manager PC 200 and the PCs comprising PC group 300, in addition tohaving a computer body that includes a hard disk (HD), a monitorconnected to the body, and a keyboard, each include a network compatibleoperating system (OS) preinstalled in the HD, a print driver, andapplication software for conducting wordprocessing and the like.

When one of the PCs in PC group 300 requests print processing of adocument created using the application software, then image data, aprint request signal, and print information is sent to server 100. Theprint information is indicated by a user and shows the number of pagesper original document, the number of copies required, an image mode(e.g. text or photograph?), and a color mode (e.g. monochrome or fullcolor?), among other information.

The image and color modes can otherwise be determined automatically froman analysis of the image data without the need for a user instruction.In this case, the image mode may be selected automatically based on theamount of halftone data in the image data, such that “text” is selectedwhen the halftone data is below a predetermined percentage, and “photo”is selected when the halftone data is above a predetermined percentage.Also, the image mode information can be set to include a number ofintermediate gradation levels between “text” and “photo.” The colormode, on the other hand, may be selected automatically based on thecolor pixel data in the image data, such that “monochrome” is selectedwhen the color pixel data is below a predetermined percentage, and “fullcolor” is selected when the color pixel data is above a predeterminedpercentage. Furthermore, both the image and color modes can be set perjob unit or per document unit.

The image data, print request signal, and print information can be sentseparately to the external apparatus selected to execute a requestedjob, or alternatively, they can be included together in a file which isthen sent to the selected apparatus.

When the job is a request for a scanner to conduct image readingprocessing, scan information showing the image mode and a resolutionmode can be sent to server 100 together with the image read requestsignal.

In addition to providing various services for the personal computersincluded in system 1, server 100 can also operate as a managementapparatus for managing the external apparatuses included in system 1.

On receipt of a print request, server 100 selects an optimal printerfrom printer group 500 based on the print information sent from the PCrequesting the job, and sends the image data received from the PC to theselected printer together with a job execution command and the printinformation.

On receipt of an image read request, server 100 selects an optimalscanner from scanner group 400 based on the scan information sent fromthe PC requesting the job, and sends a job execution command and printinformation to the selected scanner. Server 100 then receives the readimage data from the scanner and sends the read image data to the PC. Theselection of an optimal apparatus as part of the print processing andimage reading processing will be described in detail in relation to joballotment processing.

Server 100 can also send a stabilization execution command to anyscanner in group 400 and any printer in group 500 in order to have therespective apparatus execute image quality stabilization processing(hereafter “stabilization processing” or simply “stabilization”).

On receipt of a job execution command from server 100, the selectedprinter in printer group 500 forms an image on paper according to thewell known electronic photographic method. When a stabilizationexecution command is sent from server 100, the printers receiving thecommand each execute the stabilization processing and send optimaladjustment value information (hereafter “apparatus parameterinformation”) determined as a result of the processing to server 100.

The scanners in group 400 are well known apparatus that function toobtain image data by irradiating a document with an exposure lamp andreading the reflected light by means of a CDD image sensor or similarphotoelectric conversion unit. On receipt of a job execution commandfrom server 100, the selected scanner initiates the image readingoperation on the document and sends the read image data to server 100.The operation executed by a scanner on receipt of a stabilizationexecution command from server 100 is the same as that executed by aprinter. Specifically, the respective scanner executes the stabilizationprocessing and sends the resulting apparatus parameter information toserver 100.

Printers 501, 502, 503, . . . , and scanners 401, 402, 403, . . . (theseimage processing apparatus being hereafter referred to collectively as“external apparatus”) each include a nonvolatile memory unit 5011, 5021,5031, . . . , 4011, 4021, 4031, . . . (hereafter “memory”),respectively. In addition to apparatus parameter information, the memoryof each external apparatus stores machine information showing theparticular characteristics of the respective external apparatus. Themachine information includes environment variance information and imagequality attribute information, details of which will be given in a latersection.

When power is supplied, each external apparatus reads its respectivemachine information and sends the read information to server 100together with power-on information. And when power is cut, each externalapparatus sends power-off information to server 100.

Manager PC 200 includes a memory 201 that stores management informationrequired to manage system 1, examples of this information being targetimage quality level information and schedule information. Any inputtingof new management information or adjustment of existing information isconducted by the manager. When an input or adjustment is conducted,manager PC 200 sends a signal to server 100 via the network to informserver 100 of the fact. Based on the various information sent fromserver 100, manager PC 200 also manages the execution condition ofstabilization processing in an external apparatus and the groupformation condition after an execution of group formation processing(described below). Manager PC 200 can have this information displayed ona monitor if the manager so requires.

Server 100, the PCs, and the external apparatus each have their own IPaddress, and print requests and image data can be sent to the relevantapparatus by indicating the appropriate IP address.

Structure of Server 100

FIG. 2 is a block diagram showing the structure of server 100.

Server 100 includes a control unit 110, an information storage unit 120,a working memory 130, a timer 140 and a communication interface 150.

Control unit 110 controls the processing conducted in server 100 viacommunication interface 150 based on the information and commandsreceived from the external apparatuses and terminal apparatuses (i.e.PCs). For example, control unit 110 updates information stored ininformation storage unit 120, and instructs the external apparatuses toexecute jobs or conduct stabilization processing.

Working memory 130 includes a volatile RAM, and functions (i) totemporarily store information received by server 100 from the terminaland external apparatuses, and (ii) to read information from informationstorage unit 120 when control unit 110 controls the processing in server100.

Timer 140 measures a time lapse. In the group formation processing, forexample, timer 140 measures the time that has elapsed since the previousprocessing, and in the job allotment processing, timer 140 measures thetime elapsed since the previous stabilization processing.

Information storage unit 120 includes a hard disk, and functions tostore a machine information table 121, a management information table122, and a job management table 123.

FIG. 3 shows the content of machine information table 121.

Written into table 121 is information relating to each externalapparatus. This information includes environment variance information,apparatus parameter information, image quality information, a power-ontime, a prior stabilization time, a scheduled stabilization time, andgroup name information.

The environment variance information shows the degree to whichvariations in the internal environment conditions (temperature,humidity, etc.) of an external apparatus affect the quality level of animage obtained by executing a job. Here, the volatility of image qualitylevels to internal environment changes is referred to as “environmentvolatility.”

The environment volatility of each external apparatus is determinedthough pre-testing. In a printer the environment volatility can berepresented as a rate of variation in image density with respect tointernal temperature changes.

FIG. 4 is a graph showing an exemplary environment volatility of anarbitrary printer in group 500.

Internal temperature is measured along the horizontal axis and imagedensity is measured along the vertical axis. The slope of straight linesP and Q represents the environment volatility of the printer. Straightlines P and Q show the relationship between density and temperature whenthe number of printed sheets is less than ten thousand (i.e. P<10,000)and between ten and twenty thousand (i.e. 10,000≦Q<20,000),respectively.

As shown in FIG. 4, the environment volatility in the printer increaseswith increases in the number of printed sheets. This is due to thedeterioration in the sensitivity of the photosensitive drum over time,making the printer more susceptible to changes in internal temperature.

When the external apparatus is a scanner, the environment volatilityshows variations in the level of exposure with respect to internaltemperature changes, and as with the printer, the environment volatilityvaries depending on the number of read sheets.

Returning to FIG. 3, the apparatus parameter information in machineinformation table 121 shows optimal adjustment values, which asmentioned above are determined for each external apparatus by executingthe stabilization processing. Examples of such information with respectto a printer include the optimal adjustment values for the developingbias voltage in the developing unit and the grid voltage in the chargingunit.

Furthermore, it should be noted that although the apparatus parameterinformation may include the optimal adjustment value of elements otherthan those given above, for ease of comprehension, the description inthis embodiment will be limited to the optimal adjustment values for thedeveloping bias voltage in the case of a printer and the exposurevoltage applied to the exposure lamp in the case of a scanner.

Also, the description of the stabilization processing will be limited tothe determination of the optimal adjustment values for each externalapparatus.

The image quality attribute information in FIG. 3 shows the imagequality levels that can be sustained for different execution frequenciesof the stabilization processing.

FIG. 5 is a graph of exemplary image quality attribute informationrelating to printers 501 to 503.

FIG. 5 shows that when the stabilization processing is conducted everytwo hours in printer 501, an image quality level of GL1 or better can besustained. In other words, conducting the stabilization processing atintervals of longer than two hours will result in image quality levelsfalling below GL1. Thus, by conducting the stabilization processingevery four hours in printer 501, the achievable image quality level willdrop to GL2 or better.

The image quality attribute information for a printer is predeterminedby conducting tests to measure the reduction (deterioration) in imagequality under predetermined conditions of substantially continuous imageforming operation. The image quality attribute information for a scanneris predetermined through similar testing. Moreover, the image qualityattribute information can also show (a) the amount by which the imagequality level deviates from a target image quality level for a giventime period of image forming or image reading operations, or (b) thenumber of printed/read pages or image forming/reading operation timerequired for the image quality to deteriorate to a predetermined level.

As noted above, the environment variance information, apparatusparameter information, and image quality attribute information for eachexternal apparatus in machine information table 121 (FIG. 3) correspondto the information stored in the memory of individual externalapparatuses, and server 100 writes this information into machineinformation table 121 as it is received from the apparatuses. Theinformation in table 121 is then referenced as required during theexecution of the various processing operations.

The power-on time shows when power was turned on in an externalapparatus, and is determined as the time that server 100 receivespower-on information from the external apparatus. The “**” mark in table121 shows when the power was cut-off to an external apparatus, and isdetermined as the time that power-off information is received from theexternal apparatus.

The prior stabilization time shows when the stabilization processing waslast completed, and is determined as the time that apparatus parameterinformation is received from an external apparatus.

The scheduled stabilization time shows when the next stabilizationprocessing is scheduled to be conducted, and is calculated duringstabilization schedule calculation processing.

The group name information shows the names of the various groups intowhich the external apparatuses have been assigned as a result ofconducting group formation processing (described below).

FIG. 6 shows the content of the management information table 122included in server 100.

Written into table 122 is management information for each externalapparatus, and as mentioned above, includes target image quality levelinformation and schedule information. The management information is setby the manager on manager PC 200, from where it is sent to server 100and written into table 122.

The target image quality level information shows the minimum imagequality level required by the manager with respect to the imageprocessing conducted by each external apparatus. The target imagequality level together with the image quality attribute information isused as a basis for calculating the scheduled stabilization time (i.e.the time at which the next stabilization processing is scheduled to beexecuted). Moreover, the target image quality level can be setarbitrarily at any level between the high and low range shown in FIG. 5.

The schedule information in FIG. 6 is applied during the executionsequence processing to determine whether priority is given to the jobprocessing or the stabilization processing in an external apparatus. Theconditions of the schedule information are based on the scheduledstabilization time and a scheduled job initiation time.

FIG. 7 shows the content of the job management table 123 included inserver 100.

Written into table 123 is information relating to the jobs sent toserver 100. The information is written into table 123 in the order thatserver 100 receives the jobs, and includes job request terminalinformation, image mode information, color mode information, informationrelating to the number of pages per original document and the number ofcopies of the original document required, scheduled job initiationinformation, scheduled job completion information, and selectedapparatus information.

The job request terminal information shows the terminal apparatus thatsent the job request to server 100.

The information relating to image mode, color mode, the number of pagesper original, and the number of copies, is included in the printinformation and scan information sent from a terminal apparatus.

The scheduled job initiation and completion information shows thescheduled initiation and completion times of requested jobs, and iscalculated based on such information as the number of pages in theoriginal and the number of copied required.

The selected apparatus information shows the external apparatus selectedto execute the requested job. The selection of an apparatus is conductedin the job allotment processing.

The Processing in Server 100

FIG. 8 is a flowchart showing the main routine of the processingconducted in server 100.

On receipt of a signal relating to management information from managerPC 200 (step S10=“yes”), control unit 110 conducts management parameteralteration processing in order to rewrite the content of managementinformation table 122 based on the received signal (step S20).

When no signal relating to management information is received (stepS10=“no”), control unit 110 proceeds to the job request receptionprocessing (step S30).

In the job request reception processing (step S30), control unit 110receives a job request from the terminal apparatus. As described above,the information (image mode, color mode, etc.) included in the jobrequest is written into the appropriate columns of job management table123 so as to correspond to the terminal apparatus that sent the request.

In the machine information reception processing (step S40), such data asenvironment variance information and apparatus parameter information isreceived from the external apparatus and written into the appropriatecolumn in machine information table 121 so as to correspond to theexternal apparatus that sent the data.

In the group formation processing (step S50), the external apparatus areformed into groups in accordance with predetermined conditions.

In the time-based stabilization schedule processing (step S60), the nextscheduled stabilization processing time is determined for an externalapparatus.

In the job allotment processing (step S70), the optimal externalapparatus for executing the received job is selected.

In the execution sequence processing (step S80), control unit 110judges, based on the scheduled stabilization time and the scheduled jobinitiation time, whether to give priority of execution to thestabilization processing or the job, and alters the scheduledstabilization time in accordance with the result of the judgment.

In the command transmission processing (step S90), job execution andstabilization execution commands are sent to an external apparatus basedon the information stored in tables 121, 122, and 123 in informationstorage unit 120.

The external apparatus executes the job on receipt of the job executioncommand, and conducts the stabilization processing on receipt of thestabilization execution command.

In the job reception processing (step S100), control unit 110 notifies aterminal apparatus that requested a job of (a) the name of the externalapparatus selected in the job allotment processing to execute the job,and (b) information such as the scheduled initiation and completiontimes of the requested job.

After completing step 100, control unit 110 moves to step 110. In step110, control unit 110 waits until a predetermined time period haselapsed and then returns to step S10 to repeat the processing of stepsS10 to S110.

The processing of steps S40 to S80 will now be described in detail.

Machine Information Reception Processing

FIG. 9 is a flowchart showing a subroutine of the machine informationreception processing (step S40) in FIG. 8.

Control unit 110 firstly judges whether any information relating toenvironment changes, image quality attributes, apparatus parameters,power-on, or power-off has been received from any of the externalapparatuses (step S401).

If judged that such information was not received (step S401=“no”),control unit 110 moves to step S406. On the other hand, if judged thatsuch information was received (step S401=“yes”), control unit 110 judgeswhether or not the received information was apparatus parameterinformation (step S402). If judged that the received information was notapparatus parameter information (step S402=“no”), the receivedinformation is assumed to relate to an environment change, an imagequality attribute, power-on, or power-off. If the received informationincludes power-on information, control unit 110 writes the environmentvariance information and image quality attribute information senttogether with the power-on information into the corresponding row andcolumns of machine information table 121 in steps S403 and S404,respectively. Control unit 110 also writes the data showing thereception time of the power-on information into the power-on time columnin table 121 before moving on to step S406.

On the other hand, if the received information is power-off information,control unit 110 erases the environment variance information and imagequality attribute information written into table 121 in steps S403 andS404, respectively, and the time data in the power-on time column beforemoving on to step S406.

If the received information is judged to be apparatus parameterinformation (step S402=“yes”), then control unit 110 writes the receivedinformation into the apparatus parameter information column in table 121(step S405), before moving on to step S406.

In step S406, control unit 110 judges whether the processing in stepsS401 to S405 have been conducted for all of the external apparatusincluded in system 1. If “no” control unit 110 returns to step S401, andif “yes” control unit 110 returns to the main routine.

Group Formation Processing

FIG. 10 is a flowchart showing a subroutine of the group formationprocessing (step S50) in FIG. 8.

Control unit 110 firstly judges in step S501 whether power-on orpower-off information was received from any of the external apparatus inthe machine information reception processing (step S40) in FIG. 9.

If judged that such information was received (step S501=“yes”), controlunit 110 read information (environment variance information, etc.)required to conduct group formation processing from machine informationtable 121 into working memory 130 (step S503). Then based on the groupformation information, control unit 110 conducts operation mode settingprocessing (step S504) and group allotment processing (step S505) beforereturning to the main routine.

In the operation mode setting processing (step S504), control unit 110selects between managing the external apparatus registered in table 121in “group mode” or “individual mode.” If the group formation informationis environment variance information, then when the difference inenvironment variance information values (i.e. environment volatility)between an arbitrary external apparatus and another external apparatusis within a predetermined range, those apparatuses can be managed in“group mode.” On the other hand, when the difference in values is notwithin the predetermined range, the respective external apparatuses canbe managed in “individual mode.” This is only one method of conductingthe operation mode setting processing, and alternative methods will bedescribed in a later section.

“Group mode” involves all the external apparatus having a groupformation information value within a predetermined range being treatedas a group. All the apparatuses belonging to the same group are thenmanaged in a uniform manner using the same apparatus parameterinformation, for example.

On the other hand, “individual mode” involves those external apparatuseshaving a group formation information value outside the predeterminedrange being managed separately using apparatus parameter informationspecific to the respective apparatuses, for example.

In the group allotment processing (step S505), control unit 110 allotsthe external apparatuses set in “group mode” in the operation modesetting processing (step S504) into smaller groups based on the valueshown in the group formation information for each respective apparatus.If the group formation information is environment variance information,any external apparatuses that have an environment variation informationvalue within a predetermined range can be managed in the “group mode” ofthe same group, and any apparatuses have an environment variationinformation value outside the predetermined range are managed in the“group mode” of another group.

Returning to FIG. 10, if judged that power-on or power-off informationwas not received from any of the external apparatus during the machineinformation reception processing (step S501=“no”), control unit 110judges whether a time period ΔT elapsed since groups were last formedexceeds a predetermined time period T (step S502). Here, the time periodΔT can be measured by timer 140 in server 100, and the predeterminedtime T can be set by the manager, stored in information storage unit120, and read from unit 120 as required.

If the time period ΔT is judged to have exceeded the predetermined timeT (step S502=“yes”), control unit 110 executes steps S503 to S505. Onthe other hand, if step S502 is judged to be “no,” then control unit 110returns to the main routine.

As described above, control unit 110 executes steps S503 to S505 whenthe time period ΔT exceeds the predetermined time T in order to conductthe group formation processing based on the group formation information.

If the group formation information is environment variance information,the value of the information can vary depending on the number of jobsexecuted by an external apparatus. Thus if new groups are not formed inaccordance with a current value of the environment variance informationfor each apparatus, the existing groups may end up including externalapparatuses having very different environment volatilities.

By executing the group formation processing at regular intervals inserver 100, it is possible to maintain well-balanced groups even ifthere are changes in the environment variance information of individualexternal apparatuses.

FIGS. 11A and 11B show the group formation processing executed in server100 when based on environment variance information.

FIG. 11A shows an exemplary group formation conducted by server 100 on aplurality of external apparatuses, and FIG. 11B shows an example of thegroup formation processing being executed on the group formation in FIG.11A.

In FIG. 11A, printers 501 to 507 are in “group mode” and printers 508and 509 are in “individual mode.” In addition, printers 501 to 507 aredivided into groups GE1 to GE3.

The groups GE1 to GE3 each have a different value range (hereafter“group allotment range”) of the environment variance information, andany external apparatuses having a value outside of the group allotmentrange are set to “individual mode.” The external apparatuses in “groupmode” are allotted to one of the groups based on their respectiveenvironment variance information.

Here, the group allotment range can be set by the manager. Furthermore,a group allotment table can be generated in which to write informationrelating to the range, and the table can be stored in informationstorage unit 120.

FIG. 12 shows an exemplary structure of the group allotment table, whichcontains information relating to the group allotment range.

The group allotment table contains the group allotment range set withrespect to groups GE1 to GE3 using threshold values K1 to K4. Asdescribed above, the threshold values K1 to K4 can be set by themanager.

Pe in the group allotment table is the value of the environment varianceinformation.

For the purpose for the present invention the number of groups has beenset at three, although it is of course possible to have a differentnumber of groups, say, four or more groups, for instance. Moreover, itis possible for the threshold values K1 to K4 to be varied in accordancewith the operating condition of the external apparatus or the state ofthe group formation processing in server 100, for example.

In FIG. 11B, external apparatuses whose environment variance informationhas changed (printers 503, 505, 507, and 508 in the given example) sincethe group formation processing shown in FIG. 11A was executed, are setat different operation modes and allotted to different groups when thegroup formation processing is executed after a predetermined time periodon the group formation shown in FIG. 11A.

As described above, server 100 executes the group formation processingin which the external apparatuses having, for example, environmentvariance information of a similar value are treated as one group, andthe external apparatuses formed into the same group are managed byserver 100 in a uniform manner. It is this uniform management ofexternal apparatuses belonging to the same group that makes possible thesharing of apparatus parameter information in the time-basedstabilization schedule processing that will now be described.

Time-based Stabilization Schedule Processing

FIG. 13 is a flowchart showing a subroutine of the time-basedstabilization schedule processing (step S60) in FIG. 8.

Control unit 110 firstly judges whether there has been a change to theapparatus parameter information (step S601). This judgment is conductedbased on whether there was an entry of apparatus parameter informationin step S405 of the machine information reception processing (FIG. 9).

If judged that there has been a change in the apparatus parameterinformation (step S601=“yes”), control unit 110 executes processing toacquire a stabilization execution interval for the external apparatus towhich the change relates (step S602).

In this processing, the interval at which the stabilization processingis executed in an external apparatus is determined based on the imagequality attribute information written into machine information table 121and the target image quality level written into management informationtable 122.

Taking printer 501 as an example, if the target image quality level isset by the manager to correspond to GL1 in FIG. 5, the interval at whichthe stabilization processing is executed in printer 501 is determinedfrom the image quality attribute information to be two hours. Likewise,if the target image quality level of printer 503 is set so as tocorrespond to GL2, the determined execution interval is five hours.

Next, control unit 110 executes processing to calculate the scheduledstabilization time (step S603). In this processing, the prior executiontime of the stabilization processing for an external apparatus is readfrom the prior stabilization time information written into machineinformation table 121, and the read time is added to the executioninterval of the stabilization processing determined in step S602, andthe resultant time is computed to be the next scheduled stabilizationtime. Taking printer 501 as an example once more, if the priorstabilization time was 10:20 am and the target image quality level isset at GL1, the scheduled stabilization time is computed as 12:20 pmgiven an execution interval of two hours.

The information showing the computed next scheduled stabilization timefor the external apparatus is written into the corresponding row of the“scheduled stabilization time” column in machine information table 121.Although the execution interval is described above as being simply aperiod of time, it can alternatively be calculated in terms of theperiod of operating time actually spent executing image processing (e.g.image forming operations, etc.) in an external apparatus. In this case,if the execution interval of a printer is determined to be two hours, anexecution command to execute the stabilization processing can be sent tothe printer when the accumulated print output operation time of theprinter equals two hours.

When the time computed as the scheduled stabilization time is reached inan external apparatus, control unit 110 sends an execution command tothe external apparatus to execute the stabilization processing.

As described above, a stabilization execution interval corresponding toa target image quality level set by the manager is determined based onthe image quality attribute information of an external apparatus. Byhaving the external apparatus execute the stabilization processing inaccordance with the determined interval, the manager is effectively ableto adjust the image quality of image processing executed in the externalapparatus. For example, if printer 501 is used to output photographicpictures requiring a high quality level, the manager can set the targetimage quality level for printer 501 to a high level. In comparison, ifprinter 502 is used to output text images requiring a comparativelylower quality level, the manager can set the target image quality levelfor printer 502 to a lower level. It is thus possible to achieve animage quality level of a desired level or better in both printers.

Additionally, if the target image quality level is set to a low level,the interval between executions of the stabilization processing can belengthened, thereby reducing the frequency at which the stabilizationprocessing is executed and allowing for power savings to be made withrespect to the stabilization processing. Thus it becomes possible tosolve the problem of wasted power usage occurring in known systems inwhich a manager is not able to manage the printers in the system becauseof the stabilization processing being conducted independently in eachprinter in order to maintain a high image quality level, this being inspite of the fact that the manager may have been prepared to acceptlower image quality levels of print output.

Having completed calculating the scheduled stabilization time (stepS603), control unit 110 then moves on to conduct scheduled stabilizationtime adjustment processing (step S604). This processing is conducted onthe external apparatuses in the groups formed in the group formationprocessing.

FIG. 14 is a flowchart showing a subroutine of the scheduledstabilization time adjustment processing. FIG. 15 is a schematic diagramshowing scheduled stabilization time adjustment processing andstabilization processing being executed with respect to six externalapparatus (A to F, in the given example) that have been formed into twogroups E1 and E3 in the group formation processing, the stabilizationprocessing being executed in the order A, B, C with respect to group E1,and D, E, F with respect to group E3. The black squares in FIG. 15represent the execution of the stabilization processing.

For ease of understanding, the scheduled stabilization time adjustmentprocessing operation included as part of the time-based stabilizationschedule processing (FIG. 13) will be described in relation to apparatusA in group E1, given that apparatus A has executed the stabilizationprocessing and the apparatus parameter information has been changed.

In FIG. 14, control unit 110 firstly judges whether any of the externalapparatuses in the same group have executed stabilization processing(step S6041). In the given example, apparatus A has executed thestabilization processing (marked by black square 61 in FIG. 15). Controlunit 110 thus judges that stabilization has been executed in the group(step S6041=“yes”), receives the apparatus parameter information forapparatus A, and sends the apparatus parameters (i.e. the optimaladjustment values of the developing bias voltage, etc., determined as aresult of the execution of the stabilization processing) shown in thereceived information to the other apparatuses in the group (i.e.apparatuses B and C) together with an instruction to write the apparatusA parameters into their respective memories as new apparatus parameters(step S6042). In this way, apparatuses B and C share the optimaladjustment values of apparatus A, which has executed the stabilization.In should be noted that in case of a plurality of apparatuses havingexecuted the stabilization processing, the apparatus having the earliestprior execution time is selected. The arrow 62 in FIG. 15 represents theapparatus parameters of apparatuses B and C being rewritten to thechanged optimal adjustment values of apparatus A.

An external apparatus controls the control variables of the variousinternal elements (e.g. developing bias voltage of the developing unit,etc.) in accordance with the optimal adjustment values stored in itsmemory. This effectively means that apparatuses belonging to the samegroup will execute controls based on the same optimal adjustment values.

Thus by sharing the optimal adjustment values of one apparatus (e.g.apparatus A) with the other apparatuses in the group, the otherapparatuses (e.g. apparatuses B and C) are able to acquire the optimaladjustment values without having to execute the stabilizationprocessing. Acquiring the optimal adjustment values of the developingbias voltage for apparatus A means that apparatuses B and C are notrequired to generate a plurality of toner patterns of differingdensities on the surface of the photosensitive drum in order todetermine an optimal adjustment value of the developing bias voltage,for example.

Thus in comparison to known structures in which each of the externalapparatuses independently conducts stabilization processing, thestructure of the present embodiment allows for power usage to be reducedby an amount equal to the reduction in the number of stabilizationprocessing operations executed within the same group of externalapparatus. The reduction in the frequency with which the stabilizationprocessing is executed also means that less time is wasted interruptingthe image forming and image reading operations, which translates intoincreased time available for executing jobs. Moreover, time is no longerwasted waiting for a request job to be executed while a plurality ofexternal apparatuses having the same optimal adjustment values executethe stabilization processing at substantially the same time. Thus system1 as described above is able to realize efficiency increases in theexecution of jobs as well as overall performance improvements.

In order to have the external apparatuses in the same group (e.g.apparatuses A to C) execute the stabilization processing in order,control unit 110 adjusts the scheduled stabilization time of eachapparatus (step S6043).

The reason for rotating the stabilization processing operation among theexternal apparatus in the group is as follows. Depending on the size ofthe group allotment range determined using threshold values K1 to K4,there will be within the one group, apparatus having substantially thesame or similar environment variance information, for example. Repeatedsharing of apparatus parameters based on the stabilization processingexecuted by the same apparatus in the group means that the otherapparatuses in the group must always execute controls based on theapparatus parameters of a similar but nevertheless slightly differentapparatus. In this case, the shared apparatus parameters of oneapparatus are not necessarily going to match exactly the apparatusparameters that would be obtained from another apparatus executing thestabilization processing itself. These slight differences mean that theoptimal apparatus parameters are not being achieved, which may have anaffect on the image quality of image processing. Consequently, byrotating the execution of the stabilization processing among theexternal apparatuses in the same group (here, a strictly maintainedorder is not always necessary), the frequency with which one apparatusin the group executes the stabilization processing is reduced, allowingfor the prevention of less than optimal image quality conditions withrespect to individual apparatuses, and an overall improvement andstabilization of image quality in the group as a whole.

One possible method of rewriting the scheduled stabilization time of anexternal apparatus in a group involves determining the shortest of thestabilization execution intervals (e.g. TE1 in FIG. 15) acquired foreach of the apparatus in step S602 as the interval for all theapparatuses, and having the apparatuses execute the stabilizationprocessing based on the determined interval. This allows for thestabilization processing to be executed in turn by each of theapparatuses in the same group while at the same time maintaining animage quality level of at least as high if not higher than the targetlevel set by the manager.

The sharing of apparatus parameters in step S6042 and the altering ofthe scheduled stabilization time in step S6043 derive the same effectwhen executed with respect to apparatuses D to F in group E3.

Job Allotment Processing

FIG. 16 is a flowchart showing a subroutine of the job allotmentprocessing (step S70) in FIG. 8.

Control unit 110 firstly judges whether a job has been requested (stepS701). This judgment is based on the judgment conducted in the jobrequest reception processing (step S30).

If judged that a job has been requested (step S701=“yes”), control unit110 verifies as the apparatus group, all of the printers in printergroup 500 when the job is a request to execute print processing, and allof the scanners in scanner group 400 when the job is a request toexecute reading processing (step S702).

Control unit 110 then judges with respect to one of the externalapparatuses in the verified apparatus group, whether the power is “on”and whether execution of the job is possible (step S703). In order toconduct these judgments, control unit 110 refers to the power-on timecolumn of the row in machine information table 121 corresponding to theapparatus, and if power is judged to be “on,” control unit 110 thenrefers to job management table 123, and if judged that the apparatus isnot scheduled to execute another job and is not currently executing ajob (i.e. the present time not within scheduled job initiation and jobcompletion times in table 123), control unit 110 judges the apparatus tobe able to execute the requested job.

If judged that the apparatus is able to execute the requested job (stepS703=“yes”), control unit 110 reads the information showing the priorstabilization time (i.e. the time at which the stabilization processingwas last completed) from the machine information table 121 of theapparatus, calculates in step S704 the amount of time that has elapsed(hereafter “elapsed time”) since the stabilization processing was lastcompleted (i.e. difference between the present time and priorstabilization time), and temporarily stores the information showing thecalculated elapsed time in working memory 130 as information relating toan execution condition of the image quality stabilization processing inthe apparatus.

If the apparatus in the group selected by control unit 110 is judged notto be in a power-on state or not able to execute the job, (stepS703=“no”), control unit 110 moves to step S705.

In step S705, control unit 110 judges whether the processing in stepsS703 and S704 has been conducted for all of the external apparatus inthe verified apparatus group, and if “no,” control unit 110 returns tostep S703.

If the processing in steps S703 and S704 is judged to have beencompleted for all of the apparatus (step S705=“yes”), control unit 110acquires from working memory 130 the information showing the elapsedtime for each apparatus, compares the acquired elapsed times, selectsthe apparatus having the shortest elapsed time as the apparatus toexecute the requested job (step S706), and returns to the main routine.

Control unit 110 writes the information identifying the selectedapparatus into the selected apparatus information column in the row ofmanagement table 123 corresponding to the requested job.

Selecting the apparatus having the shortest elapsed time in the groupmeans that the apparatus most likely to execute the requested job at thehighest image quality level is selected. Put simply, because ofreductions in the achievable image quality of print output withincreases in operating time, the apparatus having the shortest amount oftime elapsed since the stabilization processing was last completedshould accordingly have suffered the least deterioration in achievableimage quality of print output. Thus the selection of this apparatus toexecute the requested job will allow for the job to be executed at ahigh image quality level.

FIG. 17 is a schematic diagram showing the relationship betweenoperation time and image quality with respect to three externalapparatuses A, B, and C. The zigzag lines 71 to 73 represent thevariance in image quality for apparatuses A, B, and C, respectively.Intervals T1, T2, and T3 represent the stabilization execution intervalsfor apparatuses A, B, and C, respectively. Zigzag lines 71 to 73 show acycle according to which image quality suffers reductions over time,until the respective target image quality level is reached, at whichpoint the stabilization processing is executed and the image quality isreturned to a high level.

If a job is to be executed at T by one of apparatuses A, B, and C havingthe characteristics described above, then selection of the apparatushaving the shortest elapsed time since the stabilization processing waslast conducted (i.e. apparatus C) would be expected to yield the highestimage quality of print output.

As described above, in the case that a plurality of external apparatusesis capable of executing the job, the job allotment processing accordingto the present embodiment results in the selection of the apparatuscapable of the highest image quality of print output. System 1 thusachieves a convenient and user-friendly image processing systemaccording to which it is possible to prevent the inconvenience occurringin known systems whereby the possibility of an inappropriate imagequality print output is increased because of the apparatus for executinga job being selected without knowing the achievable image quality levelsof each apparatus in the system.

In the job allotment processing as described above, the elapsed time isacquired as the information relating to the execution condition of thestabilization processing of an external apparatus, and the apparatushaving the shortest elapsed time is selected as the apparatus to executethe job. However, it is possible to acquire the information showing thetime period from the present time to the next scheduled stabilizationtime, and select the apparatus having the longest time period as theapparatus to execute the job. In this case, the same effect can beachieved as when the apparatus having the shortest elapsed time isselected, since the apparatus having the longest time period until thescheduled stabilization processing is effectively the apparatus havingthe shortest elapsed time since the stabilization processing was lastexecuted.

The scheduled stabilization time for each apparatus can be determined byreferring to machine information table 121, and the time period untilthe scheduled stabilization time readily obtained by calculating thedifference between the present time and the scheduled stabilizationtime.

In the job allotment processing as described above, control unit 110judges whether one of the external apparatuses in a verified apparatusgroup is capable of executing the requested job, and judges “yes” if nojobs are scheduled for or currently being executed by the apparatus.However, even if the apparatus is currently executing another job, itcan still be selected to execute the requested job if the elapsed timefrom when the stabilization processing was last conducted until thescheduled completion of the current job is judged to be shorter than thesame time period for the other apparatuses in the group. If an apparatuscurrently executing a job is selected to execute the requested job, theinitiation time of the request job will be delayed while waiting for theapparatus to finish executing the current job. However, the benefit isthat the apparatus capable of achieving the highest image quality ofprint output is selected to execute the requested job. In this case, theelapsed time is calculated from the prior stabilization time of eachapparatus until the scheduled completion time (i.e. instead of thepresent time) of the other job currently being executed, and theapparatus having the shorted elapsed time is selected to execute therequested job. This processing can also be structured such that theapparatus having the longest time period from the scheduled completiontime of the current job until a scheduled stabilization time can beselected to execute the requested job.

Also, if the elapsed times of all the apparatuses in the group areacquired and the apparatus showing the shortest elapsed time iscurrently executing a job, it is possible to select this apparatus ifjudged that the other apparatuses in the group are only capable ofproducing a low quality of print output.

Although the present embodiment was described above in terms of server100 computing the elapsed time for each external apparatus, it ispossible for each external apparatus to calculate their own respectiveelapsed time and send information showing the calculated elapsed time toserver 100. In this case, server 100 sends a request to each externalapparatus to send the elapsed time. On receipt of the request, eachexternal apparatus calculates the time elapsed since the stabilizationprocessing was last conducted until the present time and sends thecalculated elapsed time to server 100. After acquiring the elapsed timefor each apparatus as the information showing the current condition ofthe stabilization processing, server 100 selects the apparatus havingthe shortest elapsed time to execute the requested job. Alternatively,the apparatus having the longest time period from the present time untilthe scheduled stabilization time can be selected.

Execution Sequence Processing

FIG. 18 is a flowchart showing a subroutine of the execution sequenceprocessing (step S80) in FIG. 8.

In the execution sequence processing, control unit 110 firstly judgeswhether the next stabilization processing is scheduled close to the nextjob execution in an external apparatus (step S801). This judgment isbased on the scheduled stabilization time written into machineinformation table 121 and the scheduled job initiation time written intojob management table 123. Referring to the information in tables 121 and123, control unit 110 judges whether the difference between the twotimes is less than a threshold value A. Threshold value A can be writteninto the management information table 122 by the manager, and can be setin a range of approximately five to ten minutes, for example.

If judged that scheduled stabilization processing is close to a jobexecution (step S801=“yes”), control unit 110 then judges whether thejob volume is less than a threshold value B (step S802). Here, “jobvolume” refers to the number of pages to undergo print processing in thecase of a printer, and the number of pages to undergo reading processingin the case of a scanner. Like threshold A, threshold B can be writteninto the management information table 122 by the manager, and can be setin a range of approximately 10±5 pages, for example.

Of course the values of thresholds A and B are not limited to the valuesgiven above and can be set as required according to the state of system1.

In the present embodiment the value of the thresholds are set andwritten into management information table 122 by the manager, althoughit is possible to have the server determine these values depending onthe operation condition of each apparatus, and then write the determinedvalues into management information table 122.

If the job volume is judged to be less than threshold B (stepS802=“yes”), control unit 110 refers to job management table 123 inorder to judge whether the image mode of the job is without interruptiontext mode (step S803). If judged to be text mode (step S803=“yes”),control unit 110 judges whether the color mode is monochrome (step 804),and if “yes,” control unit 110 conducts job priority processing (stepS805), and returns to the main routine in FIG. 8.

In the job priority processing, the stabilization processing in anapparatus is conducted after the execution of the requested job, and thenext scheduled stabilization time is adjusted so that the job and thestabilization processing are executed consecutively withoutinterruption. Executing the job and the stabilization processingoperations consecutively removes the need repeat various pre-processingand post-processing operations such as reheating the heater in the heatfixing unit and restarting the various motors.

On the other hand, if judged that the job volume is equal to or greaterthan threshold B (step S802 =“no”), or not in text mode (i.e. photo;step S803=“no”), or not in monochrome (i.e. color; step S804=“no”),control unit 110 executes stabilization priority processing (step S806),and returns to the main routine.

Stabilization priority processing is the reverse of job priorityprocessing and involves the stabilization processing in an externalapparatus being conducted prior to the execution of the requested job,and the adjustment of the scheduled stabilization time so that thestabilization processing and the job are executed consecutively withoutinterruption.

As described above, when the scheduled stabilization processing isjudged to be close to a scheduled job, server 100 judges whether to givepriority to the job execution or the stabilization processing based onthe job volume, image mode, and color mode, and alters the scheduledstabilization time in accordance with the judgment results. It is thuspossible to improve the overall processing efficiency of the jobs whileat the same time maintaining an image quality level of at least thetarget image quality level if not better.

By altering the scheduled stabilization time so that the stabilizationprocessing and the job are executed consecutively without interruptionin the job priority processing and the stabilization priorityprocessing, it is possible to realize reductions in power usage as aresult of conducting the pre-processing and post-processing jointlyinstead of individually, as is the case when the stabilizationprocessing and job are not executed consecutively.

FIG. 19 shows, as an example of job priority processing andstabilization priority processing, the stabilization processing and jobbeing executed separately in an arbitrary printer in printer group 500.

FIG. 19A shows an example of the stabilization processing being executedafter the job execution, and FIG. 19B shows an example of thestabilization processing being executed prior to the job execution. Timeis marked on the horizontal axis of both diagrams.

As shown in the FIGS. 19A and 19B, when the printer executes thestabilization processing and the job in accordance with an instructionfrom server 100, various pre-processing and post-processing operationsare required.

When a print job is conducted in printer, for instance, thepre-processing involves operations such as rotating the photosensitivedrum at a predetermined speed so that the drum is idling, and thepost-processing involves such operations as cleaning the photosensitivedrum.

Much of the pre and post-processing required for stabilizationprocessing is the same as that required for a job, and as shown in FIG.20, it is possible to reduce the number of pre and post-processingoperations to one time each by having the stabilization processing andjob executed consecutively.

FIG. 20 shows as an example of the stabilization processing and jobbeing executed consecutively without interruption in an arbitraryprinter in printer group 500.

FIG. 20A shows an example of the stabilization processing being executedafter the job execution, and FIG. 20B shows an example of thestabilization processing being executed prior to the job execution.

As shown in FIG. 20A, an instruction from server 100 to execute thestabilization processing is received by the printer to coincide with thecompletion of the print job, which allows the stabilization processingto be initiated without conducting the post-processing for the printjob. Likewise, because the printer was executing a print job up untilimmediately before the stabilization processing was initiated, there isno need to conduct the pre-processing operations for the stabilizationprocessing.

In the case that the stabilization processing is executed prior to thejob as shown in FIG. 20B, it is possible to eliminate thepost-processing for the stabilization processing and the pre-processingfor the print job.

By altering the scheduled stabilization time so that the stabilizationprocessing and print job are executed consecutively without interruptionin the stabilization priority processing and the job priority processingof the execution sequence processing, server 100 is able to eliminateone of either the pre or post-processing operations for thestabilization processing and print job, thus realizing reduction inpower usage related to the execution the pre and post-processingoperations.

As described above in relation to the present embodiment, a printerexecutes processing (i.e. image forming processing or stabilizationprocessing) as soon as instructed to do so by server 100. However, ifthe printer is currently executing processing, it is possible to delaythe execution of the instructed processing until the current processinghas been completed. Thus, if the printer is currently executing imageforming processing and receives an instruction to execute stabilizationprocessing, the printer can store the instruction content in memory,read the instruction when the print job has been completed, and conductthe stabilization processing in accordance with the instruction.

Although the present embodiment has been explained in relation to aprinter, the same effect can be obtained from conducting the processingdescribed above with respect to a scanner.

The Processing Executed in an External Apparatus

FIG. 21 is a flowchart of the various processing operations conducted inan external apparatus once power has been supplied.

When power is supplied, an external apparatus executes machineinformation transmission processing, according to which both power-oninformation showing that power has been supplied and machine informationstored in the apparatus are sent to server 100 (step S1). Next, theapparatus executes stabilization processing (step S2), and when this hasbeen completed (step S3=“yes”), the apparatus sends to server 100apparatus parameter information obtained as a result of executing thestabilization processing (step S4). The apparatus then waits for anexecution instruction from server 100 relating to a job or astabilization processing operation (step S5).

If it is judged that an execution instruction has been received (stepS5=“yes”), the apparatus judges whether the received instruction is ajob execution instruction (step S6). If “yes” the apparatus executes thejob in accordance with the instruction (step S7). When execution of thejob has been completed (step S8=“yes”), the apparatus returns to step S5and waits again for an instruction from server 100.

On the other hand, if it is judged that the instruction received fromserver 100 was not a job execution instruction (i.e. it was astabilization execution instruction; step S6=“no”), the apparatusreturns to step S2. Then after executing the processing of steps S2 toS4, the apparatus waits again for an instruction from server 100 (stepS5).

If, for example, the apparatus is instructed, by means of a useroperating the power switch of the apparatus, to cut the power, theapparatus sends power-off information to server 100 and cuts the power.

Second Embodiment

Whereas the first embodiment was structured such that server 100 managedthe execution interval of the stabilization processing in an externalapparatus using time as a basis, in the second embodiment, time isreplaced by the number of image processing operations as the basis todetermine the timing of the stabilization execution. In a printer thenumber of image forming operations is used as a basis, and in a scannerthe number of image reading operations is used as a basis.

With increases in the number of image processing operations executed inan external apparatus, there occurs a reduction in the image quality ofprint output as a result of the deterioration of the photosensitive drumand other elements. Thus the same effects as the first embodiment can beachieved by calculating the execution interval of the stabilizationprocessing operation using the number of image processing operationsexecuted by an external apparatus. In this case, the external apparatusis instructed to execute the stabilization processing based on thecalculated number of image processing operations.

In the second embodiment, quantity-based stabilization scheduleprocessing (FIG. 22) of step S200 replaces step S60 in the main routineof the first embodiment (FIG. 8), the job allotment processing (FIG. 24)of step S300 replaces step S70, and the execution sequence processing(FIG. 27) of step S400 replaces step S80.

Furthermore, image quality attribute information (i.e. the unit ofmeasurement on the vertical axis of the graph in FIG. 5) used to controlthe stabilization execution timing according to the number of imageprocessing operations needs to be obtained for an external apparatusbeforehand by conducting tests, and then stored in the memory of theexternal apparatus. In the second embodiment, the fact that the imagequality attribute information is based on the number of executed imageprocessing operations distinguishes it from the image quality attributeinformation used in the first embodiment, which is determined in unitsof time.

In server 100, image quality attribute information is received from eachexternal apparatus and stored in machine information table 121. Machineinformation table 121 is also required to store a prior stabilizationnumber and a scheduled stabilization number, which replace the priorstabilization time and the scheduled stabilization time of the firstembodiment.

The prior stabilization number is the accumulated number of imageprocessing operations executed by an external apparatus up until thelast execution of the stabilization processing. The accumulated numberof image processing operations increases by an increment of one per pageof print processing in the case of a printer, and by an increment of oneper page of reading processing in the case of a scanner.

Here, server 100 manages the accumulated number of image processingoperations for an external apparatus by accumulating the number of imageprocessing operation per instructed job, and writing the accumulatednumber into information storage unit 120 so as to correspond to theapparatus instructed to execute the job. In this way, server 100 is ableto keep track of the accumulated number of image processing operationsfor each apparatus. Thus when apparatus parameter information is sentfrom an external apparatus, server 100 reads the accumulated number ofimage processing operations for the apparatus and writes the read numberinto machine information table 121 as the prior stabilization number ofthe apparatus.

Alternatively, an external apparatus can calculate and store the numberof image processing number it executes, and then when stabilizationprocessing has been executed, server 100 can acquire the accumulatednumber of image processing operations from each apparatus via thenetwork.

In contrast, the scheduled stabilization number is calculated and storedat the time that the number of image processing operations until thenext scheduled stabilization processing is calculated (step S2030), aswill be described in a later section.

The quantity-based stabilization schedule processing (FIG. 22), the joballotment processing (step S24), and the execution sequence processing(FIG. 27) are described below in the stated order.

Quantity-based Stabilization Schedule Processing

FIG. 22 is a flowchart showing a subroutine of the quantity-basedstabilization processing according to the second embodiment.

The judgment in step S2010 of whether the apparatus parameterinformation has changed is the same as in step S601, and will not bedescribed here.

In step S2020, control unit 110 executes processing to acquire astabilization execution interval. Here, the unit of measurement is thenumber of executed image processing operations.

In this processing, the stabilization execution interval is calculatedbased on both the image quality attribute information stored in machineinformation table 121 and the target image quality level stored inmanagement information table 122.

Referring to the graph in FIG. 5, if the unit of measurement marked onthe vertical axis is taken to be the number of executed image processingoperations, and if every 1H is taken to represent 100 processingoperations, then if the manager sets the target image quality level tobe GL1, the stabilization execution interval for printer 501 isdetermined to be 200 processing operations.

In the calculation of the number of image processing operations untilthe next scheduled stabilization processing (step S2030), control unit110 calculated the scheduled stabilization number by reading the priorstabilization number (i.e. the accumulated number of image processingoperations at which the stabilization processing was last executed)stored in machine information table 121 and adds to the read number thestabilization execution interval determined in step S2020. Thus if theprior stabilization number of an external apparatus is 1000 processingoperations and the stabilization execution interval is 200 processingoperations, then the scheduled stabilization number is calculated as1200 processing operations. In this case, control unit 110 sends astabilization execution command to the apparatus when the 1200^(th)image processing operation has been executed, and has the apparatusexecute the stabilization processing.

FIG. 23 is a flowchart showing a subroutine of the image processingoperation number adjustment processing (step S2040) in FIG. 22.

The processing executed in steps S2041 and S2042 is the same as that insteps S6041 and S6042, and will not be described here.

Step S2043 is the equivalent of step S6043 (FIG. 14), except that thescheduled number of image processing operations is used instead of thescheduled time.

In other words, the number of image processing operations until the nextscheduled stabilization processing is rewritten in order to have eachexternal apparatus in the same group execute the stabilizationprocessing on a rotational basis. This allows for the same effect to beachieved as in the first embodiment, in which the execution of thestabilization processing was managed using time as a basis. In otherwords, an excellent image quality can be achieved overall in theexternal apparatuses in a group, even though the apparatus parametersare being shared rather than calculated individually.

Job Allotment Processing

FIG. 24 is a flowchart showing a subroutine of the job allotmentprocessing according to the second embodiment of the present invention.

Steps S3010 to S3030 correspond to steps S701 to S703 (FIG. 16). Thuswhen judged that a job request has been received from a terminalapparatus (step S3010=“yes”), control unit 110 verifies the apparatusgroup targeted to executed the requested job (step S3020), and judgeswith respect to one of the apparatuses in the verified group, whetherthe apparatus is in a power-on state and capable of executing therequested job (step S3030).

If judged that the apparatus is able to execute the job (stepS3030=“yes”), control unit 110 reads the prior stabilization number forthe apparatus from machine information table 121, calculates thedifference (hereafter “processing operation differential”) between theread number and the current accumulated number of image processingoperations (step S3040), and temporarily stores the information showingthe calculated processing operation differential in working memory 130so as to correspond to the apparatus.

In step S3050, control unit 110 judges whether the processing of stepsS3030 and S3040 have been completed for all of the apparatuses in theverified group, and if “no,” returns to step S3030.

On the other hand, if judged “yes” for step S3050, control unit 110acquires from working memory 130 the processing operation differentialfor each external apparatus, and comparing the acquired numbers, controlunit 110 selects the apparatus having the lowest processing operationdifferential to execute the requested job (step S3060), and returns tothe main routine. Control unit 110 stores information identifying theselected apparatus in the selected apparatus information column of jobmanagement table 123.

Selecting the apparatus having the lowest processing operationdifferential means that the job is executed by the apparatus having theleast deteriorated image quality of print output.

FIG. 25 is a schematic diagram showing the relationship between imagequality and the number of image processing operations in three externalapparatuses A, B, and C. The zigzag lines 81, 82, and 83 show thevariance in image quality in apparatuses A, B, and C, respectively.Intervals P1, P2, and P3 show the stabilization execution intervals asthe accumulated number of image processing operations for apparatuses A,B, and C, respectively. Zigzag lines 81 to 83 show a cycle according towhich image quality reduces over time, until the respective target imagequality level is reached, at which point the stabilization processing isexecuted and the image quality is returned to a high level.

If, for example, a job is to be executed at P by one of apparatuses A,B, and C having the characteristics described above, then selection ofthe apparatus having the least number of executed image processingoperations since the stabilization processing was last conducted (i.e.apparatus C) would be expected to yield the highest image quality ofprint output.

FIG. 26 shows an exemplary allotment of a job to one of three externalapparatuses A, B, and C, as part of the job allotment processingaccording to the second embodiment.

The triangular marks along the time axis represent the job allotmentprocessing being executed in the order that the jobs are requested, andthe apparatus selected to execute the respective jobs is noted below thetriangular marks. Zigzag lines 91, 92, and 93 show the image qualityvariance for apparatuses A, B, and C, respectively. The sections of thezigzag lines running parallel to the time axis show the apparatuses whennot executing a job (i.e. when waiting for an job execution instructionfrom server 100). The image quality is thereby shown as being unchargedfor the periods that jobs are not being executed since the number ofimage processing operations is not increasing during these periods. Inother words, the vertical axis effectively marks the number of imageprocessing operations in addition to marking image quality.

For example, if the job allotment processing is executed at thetriangular mark 94 with respect to a requested job, then it is judgedthat all of the apparatuses A, B, and C are not currently executing jobsand therefore available to execute the requested job. In this case,apparatus B is selected to execute the job since apparatus B has theleast number of executed processing operations (i.e. the highest imagequality of print output). Similarly, if the job allotment processing isexecuted at triangular mark 95 with respected to a further requestedjob, apparatuses A and C are judged capable of executing the job (i.e.apparatus B being unavailable because of currently executing previouslyrequested job), and apparatus A having the least number of executedprocessing operations is selected to execute the job. Any further joballotment processing operations are conducted in the same manner.

Although the present embodiment was described in terms of the apparatushaving the lowest processing operation differential being selected toexecute the job, it is also possible, for example, to read from machineinformation table 121 the information showing the scheduled number ofimage processing operations before the next scheduled stabilizationprocessing, calculate the difference between the current number ofexecuted image processing operations and scheduled stabilization number(i.e. the accumulated number of image processing operations at which thenext stabilization processing is scheduled), and select the apparatushaving the highest calculated difference. This structure results in thesame effect as when the external apparatus having the lowest processingoperation differential is selected, since the apparatus having thehighest calculated difference is also effectively the apparatus havingthe least number of processing operations since the stabilization waslast executed.

Execution Sequence Processing

FIG. 27 is a flowchart showing a subroutine of the execution sequenceprocessing according to the second embodiment.

Control unit 110 firstly judges whether the volume of the job to beexecuted in an external apparatus exceeds the scheduled number of imageprocessing operations until the next scheduled stabilization processing(step S4010). In “yes” then control unit 110 calculates differential K(step S4020), and judges whether the calculated differential K is lessthan a threshold value C (step S4030). As with thresholds A and B in theexecution sequence processing according to the first embodiment (FIG.18), it is desirable for threshold C to be set by the manager andwritten into the schedule information column of management informationtable 122.

If step S4030 is judged to be “no,” (i.e. threshold K equal to orgreater than threshold C), control unit 110 executes stabilizationpriority processing (step S4070), and returns to the main routine. Onthe other hand, if step S4030 judged to be “yes,” (i.e. threshold K lessthan threshold C), control unit 110 executes the processing of stepsS4040 to S4060, and returns to the main routine.

The processing of steps S4040 to S4060 corresponds to that of steps S803to S805 in FIG. 18, and will not be described here. Also, thestabilization priority processing (step S4070) corresponds to theprocessing executed in step S806 (FIG. 18), and will not be describedhere.

Thus by executing the processing of steps S4010 to S4030, it is possibleto execute the execution sequence processing in server 100, even whenthe execution timing of the stabilization processing is determined basedon the number of image processing operations.

Furthermore, the present invention is not limited to an image processingsystem, and can be applied to a server (management apparatus) orexternal apparatus included in an image processing system. The presentapparatus can also be a method for managing a plurality of externalapparatuses. The present invention may also be a computer program forhaving a computer execute the method. Moreover, the present inventioncan also be a computer readable storage medium storing the computerprogram, the storage medium being, for example, a flexible disc, a harddisk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a semiconductormemory.

In case of the present invention being a computer program, it is notnecessary for the computer program to include all the modules for havingthe computer execute the processing described above. For example, it ispossible to have the computer execute the various processing operationsof the present invention by using a common computer program capable ofinstalling the required modules at a later date, examples of suchcomputer programs being a transmission computer program or a computerprogram included in the operating system (OS).

Variations

The present invention is, of course, not limited the embodimentsdescribed above, and may include any of the following variations.

(1) Since it is only required that the server, terminal apparatuses, andexternal apparatuses included in the image processing system of thepresent invention be connected so as to allow communication between thevarious elements, the connection does not have to be made using aspecialized cable for a LAN or similar network. The system can beapplied, for instance, by structuring the network using a methodaccording to which the terminal apparatuses and other elements carry outcommunications via a power line.

(2) The embodiments of the present invention as described above arestructured such that the manager operates manager PC 200 in order toinput management information such as a target image quality level.However, it is possible, for example, for the system to be structuredsuch that the manager inputs the management information directly intoserver 100. In this case server 100 additionally serves as a managementapparatus.

It is also possible for the system to be structured such that themanager inputs the target image quality level and other managementinformation using an operation panel included as part of an externalapparatus.

FIG. 28 shows an exemplary structure of an operation panel 520 includedin a printer. For ease of understanding, FIG. 28 only shows an inputunit 521 of the target image quality level. Input unit 521 includes keys522 and 523 for altering the target image quality level setting, and aset key 524 for setting the altered target image quality level.

When the manager operates key 522, display 525 showing the image qualitylevel being reduced to a lower value, and when the manager operates key523, display 525 shows the image quality level being increased to ahigher level. Display 525 is divided into 16 different levels, and inFIG. 28 a level three levels from the bottom is selected as the targetimage quality level. Here, level 3 will be set as the target imagequality level and stored in memory if the manager operates set key 524.

When the target image quality level of an external apparatus is set bythe manager, the external apparatus (e.g. printers, etc.) sendsinformation showing the set level to server 100. On receipt of theinformation showing the set target image quality level from theapparatus, it is desirable for server 100 to store the receivedinformation in machine information table 121.

In this structure, in which the manager uses the operation unit of anexternal apparatus to enter the target image quality level, it ispossible for the system to be structured such that the externalapparatus determines its own stabilization execution interval based onthe entered target image quality level and stored image qualityattribute information (i.e. equivalent of step S602 in FIG. 13), setsthe next scheduled stabilization time (i.e. equivalent of step S603),and executes the stabilization processing when the set time is reached.In this case, the external apparatus executes the stabilizationprocessing independently based on the entered target image qualitylevel, thus removing the need to be connected to a network.

In manager PC 200 or the external apparatuses, as the case may be, it isnot necessary to directly set the image quality level (e.g. GL1, etc.),but rather set the target image quality level according to variousapplications depending, for example, on whether or not the jobs onlyrelate to text images or monochrome prints. If the jobs only relate totext images or monochrome prints, meaning that a high image qualitylevel is not required, a low level can be automatically set, and if jobssuch as photographic images or color prints requiring a high imagequality are requested a high image quality level can be automaticallyset as the target image quality level. Thus by determining thestabilization execution interval based on the changed target imagequality level and the image quality attribute information, it ispossible to vary the timing of the stabilization processing in responseto set applications.

(3) Although the embodiments of the present invention have beendescribed in terms of the manager setting image quality levels such asGL1 and GL2 as the target image quality level, it is possible for thetarget image quality level to be set automatically. For example, theimage quality level of an external apparatus in which the default imagemode (i.e. the image mode predetermined when power is supplied or whenimage processing is not executed at a predetermined time) is text mode,can be automatically set at a low image quality level of GL2, forexample, while on the other hand, the image quality level of anotherimage processing apparatus in which the default image mode is photomode, can be automatically set at a high image quality level of GL1, forexample. In this way the image quality level can be set automatically inaccordance with the default image mode.

Alternatively, the number of scheduled jobs to be executed in text modecan be compared with the number of scheduled jobs to be executed inphoto mode, using as the unit of measurement, for example, apredetermined time, a predetermined number of jobs, or a predeterminednumber of image processing operations. Then if the majority of jobs aretext mode jobs, the image quality level can be set at a low level (e.g.GL2), and if the majority of jobs are photo mode jobs, the image qualitylevel can be set at a high level (e.g. GL1).

(4) Although the embodiments of the present invention were described interms of the group formation processing being executed using theenvironment variance information, it is alternatively possible to usethe image quality attribute information. The image quality attributeinformation shows image quality levels that can be maintained for agiven execution frequency of the stabilization processing. In otherwords, the image quality attribute information also effectively showsthe degree of image quality deterioration per unit of time or per imageprocessing operation. Thus by allotting the jobs evenly among theexternal apparatuses within a group using the image quality attributeinformation as the group formation information, it is possible toachieve a fairly even rate of reduction in image quality within thegroup, even when repeatedly using the apparatus parameter informationobtained from the same apparatus in the group. As a result, the variancefrom the target image quality level can be kept to a minimum.Furthermore, by allotting jobs to the group having a small deteriorationin image quality per unit of time or per image processing operation, andallotting the jobs evening among the apparatuses in the targeted group,it is possible to have the jobs executed by the apparatus having theleast deterioration in image quality of print output. As a result, theexecution frequency of the stabilization processing can be reduced andsaving in power usage realized for the image processing system as awhole.

(5) Although the embodiments of the present invention were described interms of the environment variance information being used as the groupformation information in the execution of the group formationprocessing, it is possible to use the image quality attributeinformation in combination with the environment variance information asthe group forming information. In this case, the external apparatuseshaving values close to the values shown in both the environment varianceinformation and the image quality attribute information are formed intothe same group, which means that even if the apparatus parametersobtained from the same one apparatus of the group are shared, it will bepossible to maintain a fairly even rate of reduction in image qualityamong the apparatus in the group.

(6) According to the embodiments of the present invention as describedabove, a server (PC) is provided as a management apparatus, and theserver executes management parameter alteration processing, job requestreception processing, machine information reception processing, groupformation processing, time-based stabilization schedule processing, joballotment processing, execution sequence processing, commandtransmission processing, and job reception processing. However, it ispossible to have a specified image processing apparatus functionadditionally as a management apparatus. In this case, the imageprocessing apparatus functioning additionally as the managementapparatus can be given priority over the other image processingapparatuses in conducting the stabilization processing, or alternativelyit is possible for the setting of the scheduled stabilization time andthe allotting of jobs to be conducted on an equal basis with the otherimage processing apparatuses.

(7) According to the embodiment of the present invention as describedabove, image density was used as the main determinant of image qualitylevels, and the determination of the optimal adjustment values of thecontrol variables was based mainly on changes in image density. However,it is alternatively possible for elements such as image positioning orcolor balance to be used in determining image quality levels, and forthe determination of the optimal adjustment values of the controlvariables to be based on changes in these elements.

(8) Although the embodiments of the present invention were describedwith reference to examples using the number of print pages for printersand the number of document pages for scanners, the present invention isnot limited to these examples. It is alternatively possible to use, forexample, the data size of the image data for a job, the number ofreceived jobs, or the total number of pages for a plurality of jobs.

(9) Although the embodiments of the present invention were describedwith respect to an image processing system in which external apparatusesbeing printers and scanners are connected to server 100, it is possibleto apply the present invention to an overall system in which imageprocessing apparatus such as copiers and facsimiles that function toexecute image quality stabilization processing are connected to server100 as external apparatuses.

Although the present invention has been fully described by way ofexamples with reference to the accompanying drawings, it is to be notedthat various changes and modifications will be apparent to those skilledin the art. Therefore, unless such changes and modifications depart fromthe scope of the present invention, they should be construed as beingincluded therein.

1. An image processing system having a management apparatus and aplurality of image processing apparatuses, the management apparatusbeing connected via a network to each image processing apparatus andincluding: a first acquisition unit for acquiring apparatus attributeinformation showing an attribute of each image processing apparatus; agroup formation unit for forming the image processing apparatuses intoone or more groups based on the acquired apparatus attributeinformation; a second acquisition unit for acquiring value informationfrom a target image processing apparatus, the target image processingapparatus being an image processing apparatus in a group, and the valueinformation relating to a control variable value required by the targetimage processing apparatus in order to execute image processing; and atransmission unit for transmitting the acquired value information toanother image processing apparatus in the group, and each imageprocessing apparatus including: a reception unit for receiving the valueinformation transmitted from the management apparatus; and an imageprocessing unit for executing the image processing based on the receivedvalue information.
 2. The system according to claim 1, wherein themanagement apparatus further includes an instruction unit forinstructing the target image processing apparatus to execute imagequality stabilization processing, the target image processing apparatusincludes a stabilization execution unit for executing the image qualitystabilization processing when instructed to do so by the managementapparatus, and the control variable value is determined as a result ofthe image quality stabilization processing executed by the target imageprocessing apparatus.
 3. The system according to claim 1, wherein themanagement apparatus further includes a time measurement unit formeasuring a time period elapsed since the groups were formed by thegroup formation unit, and the group formation unit forms new groups whenthe time period measured by the time measurement unit exceeds apredetermined time period.
 4. The system according to claim 1, whereinthe second acquisition unit changes, at a predetermined frequency, thetarget image processing apparatus to another image processing apparatusin the group, and acquires value information from the image processingapparatus determined as a result of the change.
 5. The system accordingto claim 1, wherein the apparatus attribute information shows avolatility attribute relating to a quality level of an image obtained asa result of executing the image processing in an image processingapparatus.
 6. The system according to claim 5, wherein the volatilityattribute shows an extent to which an environment change affects thequality level of the image, and the group formation unit forms thegroups based on the volatility attribute for each image processingapparatus.
 7. The system according to claim 1, wherein the controlvariable value is used to control the image processing, the execution ofwhich affects a quality level of an image.
 8. A management apparatusthat manages a plurality of image processing apparatuses via a network,comprising: a first acquisition unit for acquiring apparatus attributeinformation showing an attribute of each image processing apparatus; agroup formation unit for forming the image processing apparatuses intoone or more groups based on the acquired apparatus attributeinformation; a second acquisition unit for acquiring value informationfrom a target image processing apparatus, the target image processingapparatus being an image processing apparatus in a group, and the valueinformation relating to a control variable value required by the targetimage processing apparatus in order to execute image processing; and atransmission unit for transmitting the acquired value information toanother image processing apparatus in the group.
 9. The apparatusaccording to claim 8, wherein the management apparatus further includesan instruction unit for instructing the target image processingapparatus to execute image quality stabilization processing, the targetimage processing apparatus includes a stabilization execution unit forexecuting the image quality stabilization processing when instructed todo so by the management apparatus, and the control variable value isdetermined as a result of the image quality stabilization processingexecuted by the target image processing apparatus.
 10. The apparatusaccording to claim 8, wherein the management apparatus further includesa time measurement unit for measuring a time period elapsed since thegroups were formed by the group formation unit, and the group formationunit forms new groups when the time period measured by the timemeasurement unit exceeds a predetermined time period.
 11. The apparatusaccording to claim 8, wherein the second acquisition unit changes, at apredetermined frequency, the target image processing apparatus toanother image processing apparatus in the group, and acquires valueinformation from the image processing apparatus determined as a resultof the change.
 12. The apparatus according to claim 8, wherein theapparatus attribute information shows a volatility attribute relating toa quality level of an image obtained as a result of executing the imageprocessing in an image processing apparatus.
 13. The apparatus accordingto claim 12, wherein the volatility attribute shows an extent to whichan environment change affects the quality level of the image, and thegroup formation unit forms the groups based on the volatility attributefor each image processing apparatus.
 14. The apparatus according toclaim 8, wherein the control variable value is used to control the imageprocessing, the execution of which affects a quality level of an image.15. A management method used by a management apparatus that manages aplurality of image processing apparatuses via a network, comprising: afirst acquisition step of acquiring apparatus attribute informationshowing an attribute of each image processing apparatus; a groupformation step of forming the image processing apparatuses into one ormore groups based on the acquired apparatus attribute information; asecond acquisition step of acquiring value information from a targetimage processing apparatus, the target image processing apparatus beingan image processing apparatus in a group, and the value informationrelating to a control variable value required by the target imageprocessing apparatus in order to execute image processing; and atransmission step of transmitting the acquired value information toanother image processing apparatus in the group.
 16. The methodaccording to claim 15, wherein the apparatus attribute information showsa volatility attribute relating to a quality level of an image obtainedas a result of executing the image processing in an image processingapparatus.
 17. The method according to claim 16, wherein the volatilityattribute shows an extent to which an environment change affects thequality level of the image, and the group formation step forms thegroups based on the volatility attribute for each image processingapparatus.
 18. The method according to claim 15, wherein the controlvariable value is used to control the image processing, the execution ofwhich affects a quality level of an image.
 19. A computer programexecuted by a management apparatus that manages a plurality of imageprocessing apparatuses via a network, comprising: a first acquisitionstep of acquiring apparatus attribute information showing an attributeof each image processing apparatus; a group formation step of formingthe image processing apparatuses into one or more groups based on theacquired apparatus attribute information; a second acquisition step ofacquiring value information from a target image processing apparatus,the target image processing apparatus being an image processingapparatus in a group, and the value information relating to a controlvariable value required by the target image processing apparatus inorder to execute image processing; and a transmission step oftransmitting the acquired value information to another image processingapparatus in the group.
 20. A storage medium storing a computer programexecuted by a management apparatus that manages a plurality of imageprocessing apparatuses via a network, the computer program including: afirst acquisition step of acquiring apparatus attribute informationshowing an attribute of each image processing apparatus; a groupformation step of forming the image processing apparatuses into one ormore groups based on the acquired apparatus attribute information; asecond acquisition step of acquiring value information from a targetimage processing apparatus, the target image processing apparatus beingan image processing apparatus in a group, and the value informationrelating to a control variable value required by the target imageprocessing apparatus in order to execute image processing; and atransmission step of transmitting the acquired value information toanother image processing apparatus in the group.